Inductively coupled telautograph apparatus with stylus angle compensation



Q -Z 1970 A. E. woLLRlcl-l I ,5

INDUCTIVELY COUPLED TELAUTOGRAPH APPARATUS I 7 WITH STYLUS ANGLECOMPENSATION Filed Nov. 6, 1967 2 Sheets-Sheet 1 zz 1 /z Z// 1/ fi/ 1 I/0 1 I Wrurae ,4emuz4. l l/azzz/cw,

Irma/es! Oct. 20; 1970 Filed Nov. 1967.

A. E. WOLLRICH,

INDUCTIVELY COUPLED TELAUTOGRAPH APPARATUS WITH STYLUS ANGLECOMPENSATION I 2 SheetS -Sheet 2 United States Patent US. Cl. 178-19 10Claims ABSTRACT OF THE DISCLOSURE The structure teaches an arrangementto display manually created characters at a location remote from thecreating area. A writing board is provided having a plurality of pickupcoils arranged at opposite ends of the X and Y axes of the board. Eachcoil comprises a 'first segment in generally planar relation with thewriting board and a second segment in angular relation to the firstsegment. A writing instrument contains a switch activated by the tip ofthe instrument, the latter closing an oscillating c rcuit. Thealternating frequency emanating from the 0861ilator induces signals inthe described X and Y coils. The comparative signal strength within thecoils locates the position of the writinginstrument on the writing area.The signals are used to operate a remote display arrangement such as anoscilloscope. The writing instrument 18 provided with a secondary switchwhich may be manually closed to change the frequency of the emittedslgnal and thereby 'create a shutoff signal for the remote display.

A character display arrangement is disclosed having a manually operablepen which is used to form characters on a display board. A plurality ofpickup coils are peripherally arranged around the writing surface of theboard. A manually operable writing pen is provided having an oscillatortherein. The pen tip engaging the writing surface energizes theoscillator which emanates a magnetic field at a first frequency,inducing voltage signals in the peripherally arranged coils. Therelative signal output from the coils indicates the position of the penon the writing surface. The signals may be used to deflect the electronwriting beam of a storage or other oscilloscope and thereby display thecharacters formed on the writing board.

The invention relates to a device to create output signals varying inintensity in direct relation to the position of manually formedcharacters on a writing surface, the signals being useable to controlthe electron beam of a storage oscilloscope for remote display of thecharacters formed.

In describing the herein-disclosed device, for simplicity purposes,reference will be had to forming written characters on a writing boardfor remote display on a storage oscilloscope or other display device,e.g., a plotting device. However, it will be understood that any type ofcharacter may be displayed, that is, writing, drawings pictures, codedsignals, or the like.

Devices of the type here under consideration have been developed in theprior art. For example, a device denominated Scriptoscope was built asearly as 1952 as evidenced by an article appearing at pages 144 and 145in the July 1952 issue of Electronics magazine. While these prior artdevices displayed operating characteristics which were generallysatisfactory, the present invention presents importantly improvedfeatures relative thereto. For example, prior art writing and displaydevices produced distortions of the characters manually formed whichresulted from the movement of the writing instrument in space because ofthe mode in which the writer held the instrument in his hand.Additionally, the writing instrument employed in the prior art devicesrequired extended wire lead lines to power the unit and provide thecontrol circuitry to completely complement the operating characteristicsof the related oscilloscope.

Accordingly, it is a primary object of the invention to provide a remotewriting and display arrangement which eliminates the disadvantagesassociated with prior art devices.

It is a further object of the invention to provide a device of the typedescribed which minimizes display distortions inherent in the prior artarrangements and thus provides an extremely accurate remote display ofthe characters manually created by a writing instrument.

It is yet a further object of the invention to provide a writing anddisplay arrangement of the type described which has a novel arrangementof pickup coils physically associated with a writing area to providemeans for signal compensation resulting from the variable movement inspace of the writing instrument as the characters are created.

It is yet a further object of the invention to provide a writing anddisplay arrangement of the type described having a completelyindependent writing instrument, thus eliminating the need for theelectrical wire leads characteristic of the prior art arrangements.

These and other objects and features of the invention will becomeapparent in the course of the following description and from anexamination of the related drawings wherein:

FIG. 1 is a perspective view of a writing table incorporating theinvention;

FIG. 2 is a schematic perspective view of a typical coil configurationemployed in the structure of FIG. 1;

FIG. 3 is a circuit diagram of the electrical component of the writinginstrument utilized in the invention;

FIG. 4 is a fragmentary, partially schematic view of a typical switchingarrangement which may be employed in She writing instrument used in thedisclosed invention; an

FIG. 5 is a schematic logic and electrical block diagram of thecircuitry utilized in the invention.

Describing the invention in detail and directing attention to thefigures, numeral 10 generally indicates a writing table which comprisesa housing 12 physically encapsulating the major components of theinvention. The housing 12 is provided with a central writing surface 14on which may be positioned a piece of paper, or the like, upon which maybe manually drawn desired characters or other written information. Thewriting surface 14 of course forms part of an upper surface 16 of thehousing 12. A plurality of signal pickup coils are positionedperipherally around and in close juxtaposition to the writing surface14. The coils are shown schematically to simplify invention disclosure.In a preferred embodiment a pair of left-right coils 18 and 20 arepositioned on either side of the writing surface 14. Additionally,another pair of up-down coils 22 and 24 are positioned immediatelyadjacent the top and bottom edge of the writing surface 14. Coils 18 and20 may be alternately denominated the X- axis coils, while coils 22 and24 may be denominated Y- axis coils. In addition, a single coil 26 ispositioned immediately adjacent the writing surface 14 and totallysurrounding the latter. Its purpose will be subsequently described.

Referring to FIG. 2, a preferred physical coil construction is hereshown. It will be understood that all of the coils 18, 20, 22, and 24are physically constructed in a similar manner. Accordingly, only thestructure of coil 18 is shown in detail in FIG. 2. Coil 18, shown inFIG. 2, comprises a first winding segment 18a which is formed in a planeparallel to the surface 16 of the housing and, therefore, in a planeclosely related to and parallel with the writing surface 14. Coil 18additionally comprises a second winding segment 18b which is formed in aplane perpendicular to the plane of coil segment 18a. The purpose ofthis physical relation of the separate coil segment will hereinafter bedescribed in detail but coil segment 18a may, for convenience, be calledthe primary signal pickup coil while the coil segment 18b may be calledthe pen-tilt correction-signal pickup segment.

Turning to FIGS. 3 and 4, it will be seen that a conventional writinginstrument is shown fragmentarily at and comprises a writing ball tip 32which engages the writing surface 14 in the conventional manner. The tipof the writing instrument 30 is provided with a coil formed therein, asat 34, the latter having its exposed ends connected to a normally openswitch 36. It will be apparent that when the writing instrument 30 isphysically pressed against the surface 14 the ball 32 will move axiallythe writing instrument 30 and close the switch 36 thereby energizing thecoil 34 as is shown in circuit diagram of FIG. 3. Typically, the circuitof FIG. 3 is a conventional oscillator circuit employing a solid-statetransistor device 37. In a preferred embodiment of the invention poweris supplied by an independent battery 38 thereby eliminating the needfor wire-fed power supply to the writing instrument. The circuitadditionally comprises capacitors 40, 40, resistance 42, and a pair ofnormally open switching devices 36 and 46. It will be noted theswitching device 36 represents and is identical with that actuated bythe ball 32 of the writing instrument 30.

In normal operation, the Writing instrument 30 is hand manipulated overthe writing surface 14 which closes switch 36 energizing the coil 34 ofthe oscillator circuit shown in FIG. 3. As a result of operation of theoscillating circuit of FIG. 3, an alternating magnetic field is createdby the writing instrument 30 and at a first frequency determined by thecharacteristics of the circuit of FIG. 3, as will be well understood bythose familiar with this art. The alternating magnetic field expandingand contracting from the writing surface 14 inductively locks withpickup coils 18, 20, 22, and 24 inducing a voltage signal therein. Thesignal created in the X-axis pair of pickup coils 18 and 20 has astrength in the respective coils directly proportional to the X-positionof the writing instrument on the writing surface 14. Similarly, therespective signal strength induced in X-axis pickup coils 22 and 24 isdirectly proportional to the Y position of the Writing instrument 30 onthe writing surface 14. It will be obvious that the relative signalstrength, therefor, will continuously vary as the X-Y position of thewriting instrument is varied over the writing surface 14.

In describing the typical coil construction of FIG. 2, it will berecalled that a coil structure in perpendicular planes was said to bepresently preferred. It will be apparent that the writing instrument 30,when being manually manipulated over the write surface 14, will normallybe aligned in an acute angle relative to that surface. It has been foundthat if just parallel plane coils such as those shown in 18a in FIG. 2are used, that a signal distortion results because of the angle ofholding the writing instrument. Accordingly, coil segment 18b ispositioned in a plane perpendicular to the plane of coil segment 18aand, in this position, will normally have a minimum signal inducedtherein when the pen is held perpendicular to the writing surface 14. Asthe pen is moved from said perpendicular position to an acute angularposition relative to writing surface 14, the signal induced in writingsegment 18a is diminished while the signal induced in writing segment18b is increased. However, the total signal emanating from the coil 18represents the sum of the signals in the respective coil segments 18aand 18b and therefore the total output signal of the coil is unaffectedby the variable tilting of the pen during the manual writingmanipulation. Similarly, the total signal induced in coil-s 20, 22, and24 compensates for pen tilt.

Directing attention to FIG. 5, the coils 18, 20, 22, 24, and 26 areschematically indicated therein. The Y-axis coils 22 and 24 each delivertheir signal to an amplifierrectifier combination indicated at 50 and52. The DC. signals from rectifiers 50 and 52 are delivered to nonlinearamplifiers 54, 58, the latter delivering signals to the adder 56. Thetwo signals are arithmetically combined in the adder 56 and an outputsignal emanates therefrom to control the vertical deflection of aconventional electron beam of an associated oscilloscope. Similarly,coils 18 and 20 have their output signals delivered to amplifiers 60 and62. The output of the amplifiers is conducted to rectifiers 64 and 66.respectively, and the DC current emanating therefrom is carried tononlinear amplifiers 68 and 70, the output of the latter beingarithmetically summed in the adder 72. The summing in the adder 72produces an output signal which controls the horizontal deflection ofthe associated oscilloscope electron beam. In addition, the signals fromamplifiers 60 and 62 arising from the closing of switch 36 as thewriting process begins may be carried to amplifier mixer 74 and theoutput therefrom rectified as at 36. The rectified signal is passed vialow-pass filter 78 to a conventional control device which operatesmerely to turn on the electorn beam.

Recalling that the display device is a conventional storage tubeoscilloscope, a mode to erase the written image must be provided. Thewriting device 30 may be provided with an independent manually-operatedswitch 46, the latter being closeable by the writer to provide analternate frequency output from the coil 34 by shorting capacitor 41from the circuit comprising capacitors 40, 41 connected in series. Thisoutput induces a signal in coil 26 is tuned to this alternate frequencythus providing signal which is amplified in amplifier 80, rectified inrectifier 82, and passed via low-pass filter 84 to a conventionalcontrol device at the oscilloscope which will provide a negative bias atthe oscilloscope grid turning off the electron grid. It will beunderstood that no signal will be induced in coil 26 by the writingprocess so an erase signal cannot be generated without positive actionby the writer.

The invention as shown and described is by way of illustration and notlimitation and my be modified in many respects, all within the scope andspirit thereof.

What is claimed is: 1. In a sensing arrangement adapted to displaycreated characters at a remote display device, the combination of: acharacter-creating area, plural coil means positioned in predeterminedjuxtaposition to the area, each of said coil means having an axis andadditionally including no less than one turn on the same side of saidarea, said no less than one turn being disposed parallel to a planeoriented at an angle with said area and intersecting said axis,

character-creating means adapted to emanate an alternating magneticfield of constant amplitude thereby to induce electrical signals in allof said coil mean-s as a result of cooperation with the creating area,the induce signals in the respective coil means having variableintensity as a function of the position of said character-creating toreflect the position thereof in the creating area,

and means coupled to said plural coil means for generatingvariable-intensity direct-current signals adapted to actuate saiddisplay device and thereby reproduce the characters created.

2. A sensing arrangement according to claim 1, wherein said plural coilmeans comprises first and second coils oriented to the X-axis of thecreating area and third and fourth coils oriented to the Y-axis of thecreating area.

3. A sensing arrangement according to claim 2 wherein the first andsecond coils are positioned on opposed sides of the creating area andthe third and fourth coils are positioned on other opposed sides of thecreating area,

said first and second coils being arranged in perpendicular relationshipto said third and fourth coils. 4. A sensing arrangement according toclaim 3, wherein,

the display device is an oscilloscope having a display face and anelectron beam to illuminate said face,

the signals emanating from the first and second coils controlling themovement of the oscilloscope electron beam in one direction and thesignals emanating from the third and fourth coils controlling theoscilloscope electron beam in a direction perpendicular to saidfirst-mentioned direction.

5. A sensing arrangement according to claim 4, wherein first and secondturns of the respective first, second,

third, and fourth coils are arranged in perpendicular relation to eachother,

one of said first and second turns in each coil being in planaralignment with said creating area.

6. A sensing arrangement according to claim 5, wherein said meanscoupled to said plural coil means includes circuit means wherein thevariable signals from the first and second coils are electronicallyrectified and summed in a first adder and the variable signals from thethird and fourth coils are electronically rectified and summed in asecond adder, the signals from the respective first and second addersbeing adapted to control the electron beam of said oscilloscope.

7. A sensing arrangement according to claim 1, wherein saidcharacter-creating means comprises a writing device adapted to energizean electronic oscillating circuit in response to physical contact withthe creating area.

8. A sensing arrangement according to claim 7, wherein said writingdevice includes switch means in said oscillating circuit which may bemanually energized to provide a second alternating magnetic field,

and oscilloscope control coil mean-s in juxtaposition with said creatingarea to receive said second alternating magnetic field thereby togenerate an erase signal.

9. In a pickup arrangement adapted to display created created charactersat a remote oscilloscope by controlling the electron beam thereof, thecombination of a writing area,

X-axis coil means positioned on opposed sides of the writing area,

Y-axis coil means positioned on other opposed sides of the writing area,

each of said coil means comprising a first coil segment positioned inplanar relationship with the writing area and a second coil segmentsensitive on a parallel axis positioned in perpendicular relation to thewriting area,

a writing device comprising a tip adapted to actuate a switch uponengaging the writing area and close a battery-powered oscillatingcircuit to create an alternating magnetic field of constant amplitudeand at a first frequency, said alternating magnetic field beingoperative to induce electrical signals in the respective coil meanshaving variable intensities that are a function of the position of thewriting device in the writing area,

means responsive to said variable intensity signals from the X-axis coilmeans for generating a first variable-intensity direct-current signaladapted to control the electron beam of said oscilloscope in onedirection; and

means responsive to the variable intensity signals from the Y-aXis coilmeans for generating a second variable-intensity direct-current signaladapted to control the oscilloscope electron beam in an orthogonaldirection, whereby the characters created at the writing area aredisplayed on said oscilloscope.

10. A sensing arrangement according to claim 9, and

including,

another manually operated switch associated with said wiring deviceadapted upon closure to change the frequency of said alternatingmagnetic field of constant amplitude in said oscillating circuit to asecond frequency, and

a beam control coil associated with the writing area and tuned to saidsecond frequency to create an induced signal in response to said secondfrequency alternating magnetic field, the last-mentioned created signalbeing adapted to control the presentation of said display.

References Cited UNITED STATES PATENTS 2,000,014 5/1935 DuMont 178-182,914,610 11/1959 Leitner et al. 17819 OTHER REFERENCES A. G. Hubby etal., Scriptoscope Shows Messages on C-R Tube; Electronics, July 1952,pp. l44l45.

ALVIN H. WARING, Primary Examiner M. M. CURTIS, Assistant Examiner U.S.C1.X.R.

